Minimal important difference of Berg Balance Scale, performance-oriented mobility assessment and dynamic gait index in chronic stroke survivors

The Berg Balance Scale (BBS), Performance-Oriented Mobility Assessment (POMA), and Dynamic Gait Index (DGI) are crucial standard tools used to evaluate functional balance. However, their minimal important difference (MID) threshold is yet to be established. The objective of this research was to explore the MID for BBS, POMA, and DGI in people suffering from chronic stroke. A total of 130 chronic stroke patients were assessed using BBS, POMA and DGI before and after undergoing interventions. The treatment procedures included a series of task-oriented exercises focusing on motor re-learning. In anchor-based approach, the Clinical Global Impression of Improvement scale served as the anchor. The Receiver Operating Characteristic (ROC) curve was employed to identify the best MID cut-off point for BBS, POMA, and DGI. In the distribution-based approach, one-third standard deviation (SD), half SD, one standard error of measurement (SEM), and the total score of BBS, POMA and DGI were used to determine the MID. The MID from the ROC curve was greater than 2 points for BBS, greater than 1 point for POMA and DGI. For the distribution-based approach, the MIDs corresponding to one-third of the SD, half of the SD, and one SEM for BBS were 1.92, 3.20, and 0.90; for POMA were 1.47, 2.45, and 1.96; for DGI were 1.48, 2.47, and 1.16 points, respectively. BBS, POMA and DGI are suitable instruments for assessing functional balance in individuals with chronic stroke, with demonstrable MID. Additionally, the results indicated that DGI has higher sensitivity and specificity than the other examined scales for distinguishing between groups without change and those with minimal balance improvement after receiving interventions.